Opponents of an immigration enforcement bill protest in a Washington office building June 18, 2013. / Carolyn Kaster AP

by Alan Gomez, USA TODAY

by Alan Gomez, USA TODAY

WASHINGTON -- A "border surge" plan approved by the Senate on Wednesday to attract conservatives worried about border security has enraged liberal groups, with one even withdrawing its support for the bill.

Presente.org of Berkeley, Calif., has supported the Senate bill that allows the nation's 11 million unauthorized immigrants to get U.S. citizenship. But it says the bill has been tainted by the proposed flood of Border Patrol agents to secure the southwest border.

The group said the added presence of thousands more Border Patrol agents, fencing and surveillance technology will militarize border communities and make the legal, cross-border traffic even harder to maintain.

"As advocates for real immigration reform, we cannot, in good conscience, support a bill that's guaranteed to deepen the crisis for citizens and non-citizens living in border communities," said Arturo Carmona, executive director of Presente.org. "As the legislation moves to the House, we are drawing a line that we cannot and will not accept more extreme measures disguised as 'bi-partisan immigration reform.'"

The Senate is nearing a final vote on a sweeping immigration plan drafted by a bipartisan group of senators, known as the Gang of Eight. On Wednesday, the chamber adopted an amendment brokered by Sen. Bob Corker, R-Tenn., and Sen. John Hoeven, R-N.D., to spend $30 billion to double the size of the Border Patrol to nearly 40,000 agents and add nearly $5 billion in new surveillance technology.

Several liberal groups indicated they may follow the lead of Presente.org. For now, they only say they strongly oppose the "border surge" plan.

MoveOn.org called the amendment "disappointing" because it "wastes billions of taxpayer dollars" while making the road to citizenship even more difficult for the nation's unauthorized immigrants. 18 Million Rising, an advocacy group for Asian and Pacific Islanders in the USA, said the billions of dollars spent on the "militarization" of the border are better spent on infrastructure, education and social services.

Becky Bond, political director for CREDO Action, a group that supports and funds liberal causes, said members of the Gang of Eight "needlessly negotiated with themselves" by accepting the Corker-Hoeven amendment.

"Making concessions in advance of negotiations has certainly not proven a winning strategy for Democrats in recent fights and will only embolden the extreme right wing majority in the House of Representatives as they work to further compromise the Senate immigration bill," Bond said.

Ira Mehlman, a spokesman for the Federation for American Immigration Reform, a group that opposes the bill, sees two possibilities behind the sudden change of heart from advocates.

On the one hand, he says it's possible they're trying to "give cover" to Republicans who might vote for the bill. If immigration advocates oppose the bill, he said, a Republican could use that to justify a vote to support it.

Mehlman also said the groups are laying the groundwork for cutting back on the enforcement provisions in the bill after it becomes law. He said "from the moment the president's signature is dry on the bill" the groups would lobby to get the administration and Congress to scale back the border security portions of the bill.

"It could be a harbinger of what we would likely see a year or two after this bill is enacted, if God forbid it is enacted," Mehlman said.

Most of the larger immigration rights groups that have been lobbying Congress on the bill, like the National Council of La Raza, America's Voice and the National Immigration Forum, continue supporting the bill. The National Association of Evangelicals was hosted a prayer gathering outside the Capitol Wednesday morning, followed by a rally supporting the bill that included immigrant families and members of the Service Employees International Union.

"This bill has some really tough spots. Certain pats of the movement don't feel it's part of the price of admission," said Ali Noorani, executive director of the National Immigration Forum. "But winning legislation that's bipartisan means that not everybody is going to be happy."